Vulcanology, igneous petrology and geochemistry of silicic calderas

Research

The timescales of magmatic processes prior to a caldera-forming eruption of Santorini

My Ph.D. was on the >10 km3, 22-ka Cape Riva eruption of Santorini, Greece. I looked at a series of lavas and minor pyroclastic deposits that erupted prior to the Cape Riva. This eruptive sequence had previously been described as “precursory leaks” from a slowly growing magma reservoir that went on to feed the Cape Riva eruption itself. However, I found that these “precursory leaks” are enriched in incompatible trace elements relative to the Cape Riva, showing that they must have evolved separately. 39Ar/40Ar dates and diffusion chronometry shows that the assembly of the Cape Riva reservoir was rapid, and much of the magma arrived in the shallow system a few decades before eruption.

A complete caldera cycle at Rabaul, Papua New Guinea

During my postdoctoral fellowship, I studied Rabaul, Papua New Guinea. I found that there was a major change in the shallow plumbing system after the most recent caldera-forming eruption. In the post-caldera system, there is frequent basaltic intrusion, as opposed to andesitic recharge prior to the caldera-forming eruption. This suggests that a silicic reservoir large enough to block the rise of basalt existed before the caldera-forming eruption, but a similar reservoir is not present today under Rabaul. Currently, I am studying the pre-caldera eruptions to track the composition of the recharge and the evolution of the silicic reservoir.